Keeper for an excavator tooth



1952 F. D. STEPHENSON 3,019,537

KEEPER FOR AN EXCAVATOR TOOTH Filed Jan. 6, 1959 22 INVENTOR.

FERRALD DAN/EL STEPHENSON BY 95W d fly? A T TORNEYS United States Patent Patented Feb. 6, 1962 Ofitice 3,ttl9,d37 QEEPER AN EXtCAVATtBR TGQTH Ferrald Daniel Lakewood, Calif, assignor to American Brain: Shoe Company, New Yorir, N.Y., a corporation of fieiaware Filed fen. s, 3959, Ser. No. 735,174 3 Claims. {:Cl. 37 l l2) My invention relates to semi-permanent retaining means and is especially concerned with a device particularly adapted for use in connection with a detachable or removable excavator tooth. A device of this sort is shown as an example in my co-pending application entitled EX- cavator Tooth, filed April 28, 1958, with Serial No. 731,215, now latent No. 2,982,635.

In that environment there is provided a base on which a tooth tip is removably mounted so that the tooth tip can be removed and replaced when worn. Since ex cavators are subject to very severe usage there has always existed a problem of providing a retaining means or keeper for the detachable tooth tip effective to hold the tip firmly in place during working yet easily releasable with only ordinary tools available in the field when the tooth tip must be replaced.

It is therefore an object of the invention to provide a. keeper which is effective to hold the detachable parts together during eration yet which is readily and easily releasable when the tooth tip is to be removed.

Another object of the invention is to provide a keeper which can readily be used with excavator teeth currently in use.

Another object of the invention is to provide a keeper which can repeatedly be utilized and will retain its effectiveness during such repeated use and over a long period of time.

Another object of the invention is to provide a keeper which is easily manipulated with ordinarily available field tools.

A still further object of the invention is to provide a keeper easily fabricated and economically supplied.

Other objects, together with the foregoing, are attained in the embodiment of the invention described in the accompanying description and illustrated in the accompanying drawings in which:

FIGURE 1 is a side elevation of an excavator tooth, portions being broken away on a longitudinal, vertical section to disclose in side elevation a keeper according to the invention in its useful environment;

FIGURE 2 is a side elevation to an enlarged scale of the keeper;

' FIGURE 3 is a front elevation, to the scale of FIGURE 2, of the keeper;

FIGURE 4 is a cross section the plane of which is indicated by the line 4-4 of FIGURE 2; and

FIGURE 5 is a plan of the keeper.

The keeper according to the invention can readily be embodied in a number of different forms and has successfully been incorporated as shown and described herein.

In this instance the keeper is utilized with an excavator tooth 6 including a tooth base 7 and a tooth tip 8. The base and tip are interengaged as described more fully in my above-identified application. in such engagement the tip 8 is so positioned as to align an upper'opening 9 and a lower opening 11 with an aperture 12 formed in the tooth base 7. The alignment of the openings i and l1 With the aperture 12 is not necessarily precise, it being sufiicient that a substantial passageway is provided through the assembled tooth base 7 and tooth tip 8.

To retain the tooth tip on the base there is provided, pursuant to the invention, a keeper generally designated lid. This conveniently includes a body in the form of a wedge usually cast of manganese steel or fabricated of a good wear-resistant metal. The Wedge contour of the body 14 is in part defined by a rearward planar face 16 and a forward planar face 17 disposed so that the faces 16 and 17 converge toward the bottom face 18 of the body 14. There is provided an inclined planar top surface 19 on the body, The remaining sides are defined by parallel planar surfaces 21 and 22.

It is to be understood that the surfaces need not be precisely planar nor fiat but are as nearly of the indicated configuration as commercial requirements dictate. Slight variations from mathematically strict contour are immaterial. Preferably all of the edges and corners of the body 14 are rounded. The general size and configuration of the body 14 are such that the body can readily be introduced through the opening 9 so as to pass through the aperture 12 and to enter more or less fully into the opening 11. In this position the rearward surface 16 tends to abut the adacent portions of the tooth tip 8 defining the openings 9 and 11 whereas one or more areas of the front face i7 abut the adjacent area of the portion of the tooth base 7 partly defining the aperture 12. if necessary, the body 14 is driven substantially into the assembled position as shown in FIGURE 1 by a few blows of a hammer on the surface 19. It is dislodged from such position by a. few blows of a hammer on the lower end 18.

To provide an improved means for retaining the body 14 in its engaged position, the body is initially formed with additional surfaces such as an interior planar surface 26 merging with return-curved cylindrical surfaces 27 and 2,8, the surface 26 being substantially planar and parallel to the surface 16. The inturned surface 27 merges with an inclined surface 29 which in turn merges with a surface 31. The inturned surface 28 merges with a surface 32 substantially parallel to the surface 31. The various surfaces from 26 to 3-2 define what is in eifect an interior cavity open at both sides of the body 14- and also opening between the surfaces 31 and 32 on he forward side of the body 14. There is thus provided a relatively large interior cavity opening outwardly and forwardly through a restricb ed opening.

Designed to be lodged firmly within the cavity is a block 36 of resilient deformable material such as rubber or a rubber-like substance. While the block as can be vulcanized to the metal of the body 14, it is usually preferred to make the block 36 slightly larger than the cavity and then to deform the block slightly and force it into seated position in the cavity for frictional retention therein. The block 36 is formed with rounded ends 37 and 33 designed to interlock with the curved surfaces 27 and 28, respectively. The block 36 is also formed with a pair of inclined surfaces 39 and 41. The surface 39 in part matches the surface 29. The surfaces 39 and 4-1 converge in a forward direction and extend through the opening between the surfaces 31 and 32 to define a rounded tip 42 which extends forwardly beyond the fore most portion of the surface 17 (see FIG. 5). Preferably all of the bounding surfaces of the block 36 except the side surfaces 43 and 44 thereof are generated by a line moving always parallel to itself and parallel to the surface 16. The side surfaces 43 and 44 are parallel and are parallel also with the sides 21 and 2.2 of the body 14 although the thickness of the block is somewhat less than that of the body.

In the forwardly extending portion of the tip 42 the block 36 is provided with a metallic, helical spring 4-6. This is arranged so that its longitudinal axis 57 (FIG. 4) is parallel to the line generating the surface 26, for example, or so that the spring extends transversely of the block 36. While the spring can be positioned in various diiferent ways, it is greatly preferred to introduce the metallic spring as a loose part into the mold in which the block 36 is formed. After the spring has been deposited, the rubber-like material is introduced into the mold and vulcanization proceeds. The rubber-like material penetrates all of the interstices of the helical spring and is vulcanized to the material of the spring itself. The result is that the spring and the rubber-like material are firmly locked and vulcanized together against any dislodgment by any ordinary means. In fact, it is believed to be impossible to remove the spring from the block without destroying either one or the other. When the block with the spring imbedded therein is removed from the mold, the appearance of the spring is substantially as shown in FIGURE 3 since either some of the metal of the spring is exposed or with a very little abrasion becomes exposed since either nC layer or a very thin layer of rubber overlies the spring metal. The spring is made just slightly shorter in length than the width of the block 36 so that the ends of the spring are protected and are covered, it thus being unnecessary to provide any especial finish on the spring ends.

When the wedge body ltd is positioned as previously described with the block as and spring incorporated therewith, the exposed surfaces 51 of the metallic spring afford a good bearing against the adjacent surfaces bounding the aperture 12. in the tooth base 7, the doubly curved contour of the round spring wire making a particularly light friction sliding engagement. The wedge when finally in position is arranged so that the spring snaps into a depression 52 in the tooth base '7. In some instances a depression is not provided but a somewhat improved result is obtained by forming the depression 52 as shown in FIGURE 1.

Just prior to its engagement with the depression, the spring 46 is displaced inwardly and thus displaces the rubber-like material of the block 36, much of this displacement being laterally since the block is otherwise rather generally confined. The displacement also takes place throughout a rather substantially distributed volume of the block since the spring has an intimate interengagement therewith by reason of its numerous convolutions. The spring, being deformable in an axial direction, can yield with the lateral displacement of the rubber-like material. Furthermore, the spring may distort the rubber-like material, cocking the axis more or less in order to take care of any misalignment between the depression and the remaining bounding surfaces. Thus, despite some variations in dimensions and relative positioning of the parts, the wearing surface presented by the spring eventually is firmly lodged in the depression 52 with the rubber-like material of the block 36 sufficiently distorted as to exert a continual pressure upon the spring to hold the wedge body 14 firmly in place.

When the parts are dislodged by a hammer blow from below, the rubber-like body 36 is again distorted to permit the spring to rise out of the depression 52 and the wedge to be removed.

Pursuant to this invention there is consequently provided a keeper having a wear-resistant tip so effectively interengaged with a partially confined resilient rubber-like insert as to afford a firm lock under all circumstances and even after repeated use.

What is claimed is:

In an excavator tooth having a tooth base member and a replaceable tip member assembled thereon, and wherein said members are provided with aligned openings to afford a passageway through the assembled members, a keeper removably reposed in said passageway to hold the parts in assembled relation, said keeper having an elongated body essentially wedge shaped with end portions at one side thereof bearing against surfaces defining the openings in said tip, said keeper having a recess formed inward at the other side of the body opposite the side having the end portions aforesaid, a solid block of resilient material seated in said recess and projecting in the direction of said other side of the keeper body, a helical spring embedded in said block of resilient material so that the resilient material penetrates all interstices of the spring to firmly lock the spring to the reilient block with at most a thin film of resilient material covering the convolute portions of the spring that are outermost of the recess in said body, said coil spring having its axis extending transverse to the longitudinal axis of said keeper body, and the convolutes of said spring projecting beyond the plane of said other side of the keeper body bearing against a seating surface within said tooth base.

2. In an excavator tooth having a tooth base member and a replaceable tip member assembled thereon, and wherein said members are provided with aligned openings to afford a passageway through the assembled members, a keeper removably reposed in said passageway to hold the parts in assembled relation, said keeper having an elongated body with a rearward planar surface and a forward planar surface so oriented that said planar surfaces converge toward a narrow end of the keeper body, end portions of said keeper body on the rearward planar surface thereof bearing against surfaces defining the rear of the openings in said tip, one end portion of the forward planar surface of said keeper body bearing complementally on a surface bounding the front of one of said openings in the tip, said keeper having a recess de-v fined by inclined surfaces formed inward from a restricted opening at the forward planar surface of the body, a solid block of resilient material seated complementally in said recess to be firmly locked therein and having a narrow forward end projecting outward of said forward planar surface of the keeper body, a helical spring embedded in the narrow end of said block of resilient material so that the resilient material penetrates all interstices of the spring to firmly lock the spring to the resilient block with at most a thin film of resilient material covering the convolute portions of the spring that are outermost of the narrow end of said resilient block and the restricted opening in said body, said coil spring having its axis extending transverse to the longitdinal axis of said keeper body, and the convolutes of said spring projecting beyond the forward planar surface of the keeper body bearing against a seating surface within said tooth base.

3. In an excavator tooth having a tooth base member and a replaceable tip member assembled thereon, and wherein said members are provided with aligned openings to afford a passageway through the assembled membore, a keeper removably reposed in said passageway to hold the parts in assembled relation, said keeper having an elongated body essentially wedge shaped with end portions at one side thereof bearing against surfaces defining the openings in said tip, said keeper having an undercut recess formed inward from a restricted opening at the other side of the body opposite the side having the end portions aforesaid, a solid block of resilient material configured complemental to and seated in said recess and having a narrow end projecting beyond said other side of the keeper body, and a helical spring embedded in the narrow end of said block of resilient material so References (Zited in the file of this patent UNITED STATES PATENTS Smith May 2, 1933 Curtis Oct. 7, 1941 Taylor et al. July 27, 1943 Pfefferle et al. Oct. 18, 1955 Murtaugh Dec. 4, 1956 Davis et al. Aug. 12, 1958 Drover Mar. 8, 1960 

